QRS Time Research Articles

A novel marker to determine arrhytmia risk in elite cyclists: T peak T end

In athletes, left ventricular hypertrophy is a physiological response upon routine active sports. If the hypertrophic cardiomyopathy is not diagnosed and treated, it can lead to sudden deaths in athletes. Not so much data is known whether or not it is favorable to use of Tp-e values in order to reflect the arrhythmia risks in asymptomatic elite cyclists. The aim of this study is to examine the risks of regular bike sport on potential arrhythmia in healthy active elite cyclists and veterans by using non-invasive cardiac tests. Study groups were: healthy volunteers (group 1, n=28, mean age 35.8±4.6), active cyclists (group 2, n=27, mean age 21±3.0), veteran cyclists (group 3, n=27, mean age 29.5±7.1 yr). All groups were underwent cardiological examinations, 12 derivation ECG records, transthoracic echocardiography investigations. Tp-e interval, Tp-e dispersion, corrected Tp-e interval, QT interval and Tp-e/QT ratio were calculated from ECG records. Tp-e intervals were measured with Tangent method, corrected Tp-e interval were measured with Bazett formula. Mean Tp-e interval results were as follows according to groups 1, 2, 3; 75.0±9.3, 88.1±7.0, 83.2±8.8 ms, respectively. The Tp-e interval, cTp-e interval, Tp- dispersion, QT interval, and SLI values were significantly higher in active cyclists than the veteran cyclists and the control group (p<0.05). Both cyclist groups had also significantly higher Tp-e interval, cTp-e interval, QT interval, Tp-e/QT, QRS time and SLI values than the control group (p<0.05). Furthermore, there were significant differences in Tp-e interval, cTp-e interval, Tp-e dispersion, QT interval and SLI values between the active and veteran cyclists (p<0.05). There were significant differences in Tp-e dispersion between active cyclists and control group or veteran cyclists (p< 0.01). Arrythmia related to Tp-e interval, Tp-e dispersion, corrected Tp-e interval and Tp-e/QT ratio are associated with long-term, intense bike sport training either in active cyclists or veterans. This can also be associated with left ventricular hypertrophy in active cyclists and remnant left ventricular hpertrophy in veterans.

Real-Time Localization of VentricularTachycardia Origin From the 12-Lead Electrocardiogram.

The aim of this study was to develop rapid computational methods for identifying the site of origin of ventricular activation from the 12-lead electrocardiogram. Catheter ablation of ventricular tachycardia in patients with structural heart disease frequently relies on a substrate-based approach, which may use pace mapping guided by body-surface electrocardiography to identify culprit exit sites. Patients undergoing ablation of scar-related VT (n= 38) had 12-lead electrocardiograms recorded during pacing at left ventricular endocardial sites (n= 1,012) identified on 3-dimensional electroanatomic maps and registered to a generic left ventricular endocardial surface divided into 16 segments and tessellated into 238 triangles; electrocardiographic data were reduced for each lead to 1 variable, consisting of QRS time integral. Two methods for estimating the origin of activation were developed: 1) a discrete method, estimating segment of activation origin using template matching; and 2) a continuous method, using population-based multiple linear regression to estimate triangle of activation origin. A variant of the latter method was derived, using patient-specific multiple linear regression. The optimal QRS time integral included the first 120 ms of the QRS interval. The mean localization error of population-based regressions was 12 ± 8 mm. Patient-specific regressions can achieve localization accuracy better than 5mm when at least 10 training-set pacing sites are used; this accuracy further increases with each added pacing site. Computational intraprocedure methods can automatically identify the segment and site of left ventricular activation using novel algorithms, with accuracy within<10 mm.

Severe conduction defects requiring permanent pacemaker implantation in patients with a new-onset left bundle branch block after transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is frequently associated with cardiac conduction defects (CCD) requiring permanent pacemaker implantation (PPI). Although new-onset left bundle branch block (LBBB) is often seen, the rate of progression to severe CCD is unclear. We aimed to find clinical and electrocardiographic (ECG) parameters associated with severe CCD requiring PPI in patients with a new-onset LBBB after TAVI and assess its effect on clinical outcome. All consecutive patients undergoing TAVI who developed a new-onset LBBB were retrospectively analysed. We excluded patients with pre-existing bundle branch block or pacemaker. Patients were divided into two groups: with or without PPI after TAVI. We included 155 patients (50% female, 80 ± 7 years), of which 37 (24%) developed CCD requiring PPI, mainly due to a total atrioventricular block (n = 17; 46%). Cardiac conduction defects requiring PPI were associated with the following pre-existing parameters: atrial fibrillation (AF), the use of digoxin, CoreValve implantation, and left heart axis. Furthermore, it was associated with the following post-procedural parameters: left heart axis, lower mean heart rate, and prolonged PQ and QRS times. During follow-up, patients with PPI showed a lower mortality rate (11 vs. 29%, P = 0.03). In patients without PPI, mortality was lower in those with narrower QRS complex and transient LBBB. The severity and persistence of a new-onset LBBB after TAVI is associated with mortality. Cardiac conduction defects requiring PPI are associated with prior AF, the use of digoxin, CoreValve implantation, and a left heart axis. In these patients, PPI portends a better prognosis than no PPI.

The Relationship Between Cardiac Conduction Times, Cardiovascular Risk Factors, and Inflammation in Patients with Early Arthritis.

To investigate the prevalence of conduction disorders in patients with early arthritis and the relationship with inflammation and traditional cardiovascular (CV) risk factors. Patients with rheumatoid arthritis (RA) have a 2-fold higher risk of sudden cardiac death, possibly owing to conduction disorders. This increased risk might already be present at the clinical onset of arthritis. Therefore, we assessed electrocardiography, blood pressure, 28-joint Disease Activity Score (DAS28), lipid profile, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in 480 patients with early arthritis at baseline and after 1 year. The prevalence of conduction disorders was 12.5%. Conduction times at baseline were not associated with DAS28, ESR, or CRP levels and did not change during antirheumatic treatment. Baseline and the improvement in DAS28 (European League Against Rheumatism response), ESR, and CRP were significantly associated with heart rate, lipid profile, and blood pressure. Elevated total cholesterol and blood pressure were associated with an increased QRS time. The change in heart rate differed 7.3 bpm between patients with the least versus largest DAS improvement. The prevalence of conduction disorders in patients with early arthritis was 12.5%, which is similar to the general population and was not associated with changes in inflammation markers. However, a high cholesterol was associated with a prolonged QRS time. Therefore, the emphasis of CV risk management in arthritis should not be only on treatment of disease activity but also on traditional CV risk factors. The relationship between the improvement in disease activity and heart rate is remarkable because this could imply a 10-year CV mortality risk difference of 24%.

89-06: Assessment of vectorcardiographic parameters of the paced QRS complex as prediction of acute hemodynamic response in CRT patients

Purpose of the study: Vectorcardiography (VCG) has been recently reported as a promising tool to predict acute hemodynamic response in CRT patients. We evaluated the ability of 9 VCG parameters in addition to QRS duration of the biventricular (BV) paced QRS complex to predict acute hemodynamic CRT response. Methods: VCG parameters from 753 BV paced electrocardiograms (25 patients, in each patient 5 BV, 1 multispot, 1 multivein setting and each setting at 5 different atrioventricular delays) were calculated according to Frank orthogonal lead system using custom made software. Maximum vector amplitude (VA) and maximum QRS area (AREA) in the frontal (X), horizontal (Y) and left sagittal plane (Z) and in 3D projection (3D) were measured. Additionally global QRS duration (QRSD) and time from maximum peak amplitude to the end of the QRS complex were assessed (TMax). For every VCG parameter the difference (Δ) between the BV paced and atrial paced QRS-complex was calculated. VCG-parameters were compared to changes in left ventricular pressure, expressed as dP/dt max. An increase of 10% in dP/dt max was considered as acute hemodynamic response (AHR). Results: All patients had an indication for CRT according to current ESC/AHA guidelines (84% male, 100% LBBB, mean QRSD 180 ± 25ms, 40%/60% NYHA II/III). Hemodynamic response was observed in 655 (84%) of the BV paced electrocardiograms. From all vectorcardiographic parameters VA3D, ΔVA3D, AREAZ, ΔAREAZ, ΔAREA3D, TMax and ΔQRSD differentiated AHR response from non-response (Table 1). The diagnostic accuracy to predict response was the highest for ΔAREAZ (AUC = 0.799), and ΔAREA3D (AUC = 0.723) (Table 1). Conclusion: Reduction in QRS area, measured in the left sagittal plane or in 3D projection, during BV pacing seems a useful VCG parameter to predict acute hemodynamic response in CRT patients. This method may be an easy, non-invasive tool for CRT optimization.

Electromechanical Resynchronization with High Energy Septal Pacing

Background: Standard cardiac pacing in the right ventricular apex alters electrical synchrony generating left bundle branch block that in some cases causes mechanical dyssynchrony. Pacing taking into account the anatomy (septal pacing) and with enough energy to narrow the QRS complex could have a beneficial effect, improving electrical and mechanical synchrony,and consequently myocardial function.Objective: The aim of this study was to evaluate acute electrical, mechanical and hemodynamic behavior in patients with severe intraventricular conduction disorders treated with high-energy septal pacing, and compare it with other pacing sites in the right ventricle (apex and outflow tract).Methods: Thirty patients whose average age was 65 years were continuously analyzed. They were divided into: Group I (n=15) with severe conduction disorders, complete left bundle branch block or complete right bundle branch block associated with left anterior hemiblock, all with dilated cardiomyopathy and ejection fraction (EF) <35%, and Group II (n=15) without conduction disorders and preserved EF.All patients underwent an electrophysiological study where the following parameters were evaluated in the acute phase: QRS duration in ms, time between the onset of surface QRS or spike and the most distal sites of the basal left ventricular (LV) wall, measured in the coronary sinus (R-LV), isovolumic contraction time (ICT) and ejection fraction measured by tissue Doppler echocardiography (performed off-line by an echocardiography specialist) and LV dP/dtmax assessed with an intracardiac Millar catheter (only in 18 cases). All these variables were evaluated at baseline (without pacing), with high energy septal pacing (7.5 V and 1 ms pulse width), and with right ventricular apical and outflow tract pacing. High energy pacing was used to evaluate the thresholds for QRS “narrowing”.Results: In Group I, QRS, R-LV and isovolumic contraction times improved with high energy septal pacing, but not with pacing in other sites, even with improved EF. Conversely, in Group II without conduction disorders, high energy septal pacing did not prolong QRS, R-LV or isovolumic contraction times, nor improved EF, but these parameters increased with pacing in other sites.Left ventricular dP/dtmax showed an average increase of 14% in 16 of the 18 patients evaluated in the acute phase.Conclusions: In patients with severe conduction disorders and low ejection fraction (EF), septal pacing allows electromechanical resynchronization with improved EF and dP/dtmax. In patients without conduction disturbances, this septal pacing does not modify electrical synchrony while pacing in other sites such as the right ventricular apex and outflow tract impairs it.

QRS and QT ventricular conduction times and permanent pacemaker therapy after transcatheter aortic valve implantation

Abstract Transcatheter aortic valve implantation is a therapy for patients with reduced left ventricular ejection fraction and symptomatic aortic stenosis. The aim of the study was to compare the pre-and post- transcatheter aortic valve implantation procedures to determine the QRS and QT ventricular conduction times as a potential predictor of permanent pacemaker therapy requirement after transcatheter aortic valve implantation. QRS and QT ventricular conduction times were prolonged after transcatheter aortic valve implantation in heart failure patients with permanent dual chamber pacemaker therapy after transcatheter aortic valve implantation. QRS and QT ventricular conduction times may be useful parameters to evaluate the risk of post-procedural ventricular conduction block and permanent pacemaker therapy in transcatheter aortic valve implantation.

Relationship of fragmented QRS with prognostic markers and long-term major adverse cardiac events in patients undergoing coronary artery bypass graft surgery.

Fragmented QRS (fQRS) complex is associated with increased sudden cardiac death, recurrent cardiovascular events, morbidity and mortality. However, the prognostic role of fQRS has not been comprehensively studied in patients undergoing coronary artery bypass graft (CABG) surgery. In this study, we planned to investigate the relationship of fQRS with prognostic markers and long-term major adverse cardiovascular events (MACEs) following isolated CABG surgery. Two hundred and thirteen patients who underwent CABG surgery at our institution were enrolled consecutively. MACE was defined as cardiac death, recurrent myocardial infarction, decompensated heart failure and re-hospitalization. The patients were followed up for a mean duration of 26 ± 10 months for MACE. Patients with fQRS had a higher rate of Q wave on ECG (30 vs. 10%, P < 0.001), more prolonged QRS time (99 ± 11 vs. 88 ± 13 ms, P < 0.001), higher EUROSCORE (4.0 ± 1.9 vs. 2.7 ± 1.5, P < 0.001) and lower left ventricular ejection fraction (44 ± 12 vs. 56 ± 12, P < 0.001) in comparison with patients with non-fQRS. In addition, patients with fQRS had increased short-term and long-term MACE (17 vs. 4%, P = 0.002; 23 vs. 6%, P < 0.001, respectively) after discharge. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of fQRS for predicting MACE were 67, 71, 23, 94 and 70%, respectively. fQRS [odds ratio (OR) 3.110, 95% confidence interval (CI) 1.157-8.362, P = 0.025] and prolonged QRS duration (>100 ms) (OR 3.898, 95% CI 1.463-10.39, P = 0.007) were the only independent predictors of long-term MACE in multivariate logistic regression analysis. However, QRS duration had a better association with MACE than the presence of fQRS. fQRS and prolonged QRS duration may have an additional value in predicting cardiac status and long-term prognosis. Fragmentations on admission ECG and prolonged QRS duration may be useful for identifying patients with higher long-term risk who will need more intense treatment and close follow-up after CABG surgery.

High-Density Mapping of Ventricular Scar

Surviving myocytes within scar may form channels that support ventricular tachycardia (VT) circuits. There are little data on the properties of channels that comprise VT circuits and those that are non-VT supporting channels. In 22 patients with ischemic cardiomyopathy and VT, high-density mapping was performed with the PentaRay catheter and Ensite NavX system during sinus rhythm. A channel was defined as a series of matching pace-maps with a stimulus (S) to QRS time of ≥40 ms. Sites were determined to be part of a VT channel if there were matching pace-maps to the VT morphology. This was confirmed with entrainment mapping when possible. Of the 238 channels identified, 57 channels corresponded to an inducible VT. Channels that were part of a VT circuit were more commonly located within dense scar than non-VT channels (97% versus 82%; P=0.036). VT supporting channels were of greater length (mean±SEM, 53±5 versus 33±4 mm), had higher longest S-QRS (130±12 versus 82±12 ms), longer conduction time (103±14 versus 43±13 ms), and slower conduction velocity (0.87±0.23 versus 1.39±0.21 m/s) than non-VT channels (P<0.001). Of all the fractionated, late, and very late potentials located in scar, only 21%, 26%, and 29%, respectively, were recorded within VT channels. High-density mapping shows substantial differences among channels in ventricular scar. Channels supporting VT are more commonly located in dense scar, longer than non-VT channels, and have slower conduction velocity. Only a minority of scar-related potentials participate in the VT supporting channels.

Comparison of the “Real-life” Diagnostic Value of Two Recently Published Electrocardiogram Methods for the Differential Diagnosis of Wide QRS Complex Tachycardias

The diagnostic values of the aVR lead or "Vereckei algorithm," and the lead II R-wave peak time (RWPT) criterion, recently devised for the differential diagnosis of wide QRS complex tachycardias (WCTs), were compared. A total of 212 WCTs (142 ventricular tachycardias [VTs], 62 supraventricular tachycardias [SVT], and eight preexcitation SVTs) from 145 patients with proven electrophysiologic diagnoses were retrospectively analyzed by seven examiners blinded to the electrophysiologic diagnoses. The overall test accuracy of the Vereckei algorithm was superior to that of the RWPT criterion (84.3% vs. 79.6%; p = 0.0003). The sensitivity of the Vereckei algorithm for VT diagnosis was greater than that of RWPT criterion (92.4% vs. 79.1%; p < 0.0001). The negative predictive value (NPV) for the Vereckei algorithm was also greater (77.8%; 95% confidence interval [CI] = 73.6% to 82.1%) than that of the RWPT criterion (61.6%; 95% CI = 57.6% to 65.6%). The specificity of the Vereckei algorithm was lower than that of the RWPT criterion (64.7% vs. 80.9%; p < 0.0001). The positive predictive value (PPV) was also lower for the Vereckei algorithm (86.4%; 95% CI = 84.4% to 88.4%) than for the RWPT criterion (90.9%; 95% CI = 89.1% to 92.8%). Incorrect diagnoses made by the Vereckei algorithm were mainly due to misdiagnosis of SVT as VT (65.7% of cases), and those made by the RWPT criterion were due to the more dangerous misdiagnosis of VT as SVT (72.5% of cases). The Vereckei algorithm was superior in overall test accuracy, sensitivity, and NPV for VT diagnosis and inferior in specificity and PPV to the RWPT criterion. All of these parameters were lower in "real life" than those reported by the original authors for each of the particular electrocardiographic methods.

High-amplitude left ventricular pacing in cardiac resynchronization therapy: an alternative way to increase response rate in non-responders.

This study compared patients who underwent cardiac resynchronization therapy (CRT) by high-amplitude left ventricular (LV) pacing with those who underwent CRT by standard LV pacing. We included 32 CRT patients with ejection fraction (EF) ≤35%, QRS time ≥120 ms, and New York Heart Association (NYHA) class III/IV symptoms of heart failure despite optimal medical treatment. These patients were evaluated clinically and echocardiographically before, three and six months after CRT. At the 3(rd) month, the LV pulse amplitude value was set high at 5 volt for 16 patients [high-amplitude Group (HAG)], while for the other 16 patients, it was reduced to at least twice the threshold value at ≤2.5 volt [low-amplitude group (LAG)]. Clinical and echocardiographic response rates of HAG and LAG after CRT were similar in the 3(rd) and 6(th) month. In both groups, increase in LVEF and decrease in LV ESV in the 3(rd) and 6(th) month were statistically significant compared to those before CRT, and NYHA class and end-diastolic volume (EDV) was significantly reduced in the 6(th) month compared to those before CRT. However, NHYA class and EDV continued to reduce significantly in HAG from the 3(rd) to the 6(th) month (P<0.05), while the decrease in LAG was not significant (P>0.05). The rate of mitral regurgitation (MR) was reduced significantly in HAG in the 6(th) month compared to that before CRT, while the decrease in LAG was not significant (P<0.05; P>0.05 respectively). CRT by high-amplitude LV pacing was more effective according to clinical and echocardiographic evaluations. It should be considered as an alternative in non-responsive patients.

Arrhythmogenic cardiomyopathy with reduction of connexin40 and altered ion channel expression due to an inactivation of cyclase-associated protein 2

Purpose: The inactivation of Cyclase Associated Protein 2 (CAP2) by a gene trap approach (gt) in the mouse leads to a cardiomyopathy with morphological predominance of the right ventricle resulting in an increased mortality. The purpose of our investigation was to identify potential arrhythmogenic reasons leading to this premature cardiac death. Methods: We performed in vivo electrophysiological studies in CAP2gt/+, CAP2gt/gt and corresponding Wild Type (WT) mice to determine surface and intracardiac ECG parameters and to test the inducibility of Ventricular Tachycardias (VTs). Long-term-ECG recordings were used to detect spontaneous arrhythmias. mRNA expression analysis of Cardiac Connexins (Cx) and ion channels were carried out as well as quantitative cardiac fibrosis determination. Immunofluorescence of Cx40 and Cx43 was performed to visualise their distribution pattern. Results: In comparison to WT, CAP2gt/gt showed marked conduction delays on atrial and ventricular level (reduced heart rate, prolonged PQ, QRS and QT time). AV-time prolongation was due to an infra Hisian conduction delay. Functional testing revealed a trend towards a prolonged ventricular refractory period. The inducibility of VTs was significantly higher in the mutant mice. Long-term-ECG recordings showed polymorphic premature ventricular contractions and spontaneous VTs in the CAP2 deficient mice. Compared to WT, the ventricles of CAP2gt/gt mice presented enhanced myocardial fibrosis (9.1±6.7% vs. 5.6±3.3%; p=0.01) that was found predominantly in the left ventricle. CAP2gt/gt resulted in a significant reduction of Cx40 expression (septum area) and elevated ventricular expression of Cx43, desmin and the calcium channel Cav 1.2. Conclusions: Loss of CAP2 results in marked electrophysiological disturbances leading to malignant ventricular arrhythmias. Impaired sinus node function, conduction delays, and susceptibility to arrhythmias are in accordance with a reduction of Cx40 and alterations in Cx43 and calcium channel expression. Cases of right ventricular cardiomyopathy may be due to dysfunction of CAP2, so further evaluation of its influence on cardiomyopathy and arrhythmogenesis should ensue to fully understand its functioning.

High density mapping of ventricular scar- a comparison of ventricular tachycardia supporting channels with channels that do not support VT

Introduction: Surviving myocytes within scar may form channels that become critical component of a ventricular tachycardia (VT) reentrant circuit. There is little data on the physiognomies of channels that comprise VT circuits and those which are non-VT channels. Methods: Twenty-two patients with ischemic cardiomyopathy (LVEF 32±8%) and multiple inducible VT (n=73) were evaluated. Left ventricular endocardial mapping was done with high-density PentaRay™ catheter connected to the Ensite Velocity™ system. Pacing was done from bipoles showing low voltage (≤1.5V) with late potentials and/ or fractionation. A channel was defined as series of matching pace-maps with stimulus (S) to QRS time ≥40ms. Sites were determined to be part of VT channel if there were matching pace-maps to the induced VT morphology. This was confirmed with entrainment mapping when possible. The anatomical and electrophysiologic properties of these channels were evaluated. Results: A mean of 760±205 voltage points were taken, with 431±137 within dense scar (≤0.5mV). Overall 2507 pace maps (114±62 per patient) were performed. Of the 238 channels identified, 57 channels corresponded to an inducible VT. Channels that were part of a VT circuit were of greater length (mean 52±31 vs 36±26mm), had longer S-QRS (73±60 vs 62±25ms), longer conduction time (108±90 vs 35±25ms) and slower conduction velocity (CV) (0.7±0.5 vs 1.3±1.1m/s) than non-VT channels (p 80ms was 5.3 times higher in a VT channel relative to an unshared non-VT channel (95% CI 2.6 to 10.6, p<0.01). VT channels were more commonly located within dense scar (95% vs 81% non-VT channels, p=0.04). Of all the fractionated (mean 130±105) late (mean 10±5) and very late (mean 4±3) potentials located in scar, only 22%, 30% and 35% respectively were recorded within VT channels. Compared to elsewhere within the scar, in the region of VT channels fractionated potentials were longer in duration (104±26ms vs 95±26ms, p<0.001), and very late potentials were poorly coupled (309±159ms vs 240±119ms, p=0.04) to the intrinsic QRS. Following ablation targeting channels, the clinical VT was abolished in 95% of patients, and no VT could be induced in 64%. Conclusion: High density mapping shows substantial differences among channels in ventricular scar. Channels supporting VT are more commonly located in dense scar, longer than non-VT channels, and have slower CV. Only a minority of scar related potentials participate in the VT supporting channels. These findings have pertinent implications for substrate based ablation strategies.

GW24-e0778 Narrowing QRS complex by biventricular pacing combining AV node intrinsic conduction in patients with cardiac resynchronisation therapy

ObjectivesTo evaluate the impact of biventricular pacing combining AV node intrinsic conduction (the combination mode) on width of QRS complex in patients with cardiac resynchronisation therapy (CRT).MethodsAll patients with congestive...

Relationship between fragmented QRS complexes and left ventricular systolic and diastolic functions

Fragmented QRS complexes (fQRS) have been associated with increased morbidity and mortality, sudden cardiac death, and recurrent cardiovascular events. The association between left ventricular systolic and diastolic functions and presence of fragmented QRS has not been comprehensively studied to date. We tested the hypothesis that the presence of fragmented QRS is associated with left ventricular systolic and diastolic dysfunction. The study included 259 patients who were consecutively admitted to our outpatient clinic for cardiovascular risk factor management. Extensive echocardiographic parameters were obtained from all patients and these were compared with the presence and number of fQRS. Patients with fQRS were of older age (58 ± 12 vs. 55 ± 13 years, p = 0.03) and had prolonged QRS time (105 ± 12 vs. 93 ± 10 ms, p < 0.001) and a higher rate of Q waves on ECG (36% vs. 11%, p < 0.001). In addition, they had worse systolic (lower LVEF%, 44 ± 17 vs. 61 ± 12, p < 0.001) and diastolic functions (DT, 177 ± 77 vs. 211 ± 59 ms, p < 0.001; IVRT, 81 ± 27 vs. 92 ± 22 ms, p = 0.001; Em, 9 ± 4 vs. 10 ± 4 cm/s, p = 0.008; E/Em ratio, 11 ± 5 vs. 8 ± 4, p < 0.001) in comparison to patients with nonfragmented QRS. There was a significant negative correlation between the number of fQRS and left ventricle systolic functions (for LVEF%, r = - 0.595, p < 0.001). After adjustment for age and gender, the number of fQRS remained significantly negatively associated with left ventricular systolic and diastolic functions. We found that fQRS is related to left ventricular systolic dysfunction and diastolic dysfunction. fQRS, which may be the result of myocardial ischemia or scar on myocardial electrical parameters at the cellular level, may represent inadequate systolic and diastolic functions.

Age-related changes in QRS and QTc interval times observed in isolated rabbit hearts after induction of ventricular fibrillation and spontaneous conversion to sinus rhythm

Age-related changes in QRS and QTc interval times observed in isolated rabbit hearts after induction of ventricular fibrillation and spontaneous conversion to sinus rhythm

Fragmented QRS may predict postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass graft surgery

Fragmented QRS complexes (fQRS) are defined as various RSR' patterns in 2 contiguous leads corresponding to a major coronary artery territory. Although the reason of association between fQRS and cardiac events was documented as cardiac fibrosis, the predictive role of fQRS was not studied for postoperative atrial fibrillation (POAF) which is a frequent and serious complication in patients undergoing isolated coronary artery bypass graft (CABG) surgery. Therefore, this issue was investigated in the present study. The current study has a prospective observational design. Two hundred and seventy two eligible patients who underwent isolated CABG surgery were enrolled consecutively. The patients were divided in two groups with post-op atrial fibrillation (AF) and non-AF. The occurrence of new-onset AF following CABG and the relationship with fQRS were searched. The logistic regression analysis was used to determine independent predictors for POAF. The sensitivity and specificity of study variables in predicting POAF were calculated using a receiver-operating characteristic curve (ROC). POAF occurred in 62 of 272 patients (22.8%). Patients with POAF were generally older (p<0.001) and female (p=0.006), with preexisting hypertension (p=0.008), lower hemoglobin levels (p=0.011), chronic obstructive lung disease (p=0.003), prolonged QRS time (p=0.004), and higher EUROSCORE (p<0.001) compared to non-AF patients. Patients with POAF had lower left ventricular ejection fraction (p<0.001) and high fQRS rate (p<0.001), but similar left atrial size (LA, p=NS). Interestingly, LA size was significantly enlarged in patients with fQRS (3.8±0.6 vs. 4.1±0.5 cm, p=0.002). In addition, the patients with POAF had prolonged stay in the cardiac surgery intensive-care unit (p<0.001) and extended in-hospital care (p=0.001). New-onset POAF was significantly related to the presence and number of fQRS. In the logistic regression analysis, only age (OR: 1.044, 95% CI: 1.008-1.082, p=0.016), female gender (OR: 2.347, 95% CI: 1.079-5.106, p=0.031), the presence and number of fQRS (OR: 6.020, 95% CI: 3.152-11.5 and OR: 1.522, 95% CI: 1.282-1.807, both of, p<0.001) were independent predictors of POAF. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and the diagnostic accuracy (DA) of presence of fQRS on pre-op electrocardiogram to predict POAF were 66%, 76%, 45%, 88% and 74%, respectively. The area under ROC was found as 0.733 (p<0.001, 95% CI: 0.657-0.810). In our study, we found that new-onset POAF was independently related to the presence and number of fQRS in patients undergoing CABG surgery. In addition, fQRS on pre-op surface ECG had high predictive values for new-onset POAF.

Relationship of fragmented QRS with prognostic markers and in-hospital MACE in patients undergoing CABG

Background. Fragmented QRS complex (fQRS) is associated with increased morbidity and mortality, sudden cardiac death and recurrent cardiovascular events. However, its prognostic role has not been studied comprehensively in patients undergoing coronary artery bypass graft (CABG) surgery. In this study, we investigated the relationship between the presence of fQRS, and the prognostic markers and in-hospital major adverse cardiovascular events (MACE). Methods. Two hundred and forty two eligible patients who underwent CABG surgery at our institution were enrolled consecutively. In analysis of fragmentations on electrocardiograms, presence of fQRS was defined as various RSR′ patterns (≥ 1 R′ or notching of S wave or R wave) with or without Q waves without a typical bundle-branch block in two contiguous leads corresponding to a major coronary artery territory. MACE was defined as cardiac death, recurrent myocardial infarction, heart failure, cerebrovascular event, sustained ventricular tachycardia or fibrillation. Results. Patients with fragmented QRS had older age (64 ± 10 vs. 61 ± 9 years, p = 0.03), prolonged QRS time (99 ± 11 vs. 87 ± 11 ms, p < 0.001), higher rate of Q wave on ECG (29% vs. 12%, p = 0.001), higher European system for cardiac operative risk evaluation (EUROSCORE) (4.0 ± 1.9 vs. 2.6 ± 1.6, p < 0.001) and lower left ventricular ejection fraction (LVEF)% (43 ± 12 vs. 60 ± 12, p < 0.001) in comparison to patients with non-fragmented QRS. In addition, the patients with fQRS had longer cross-clamp time (67 ± 23 vs. 55 ± 20 minutes, p = 0.001) and extracorporeal circulation (105 ± 31 vs. 91 ± 30 minutes, p = 0.003), increased inotropic usage (p < 0.001) and prolonged cardiac surgery intensive care unit (53 ± 25 vs. 35 ± 12 hours, p < 0.001) and in-hospital stay after CABG. Conclusion. FQRS may have additional value in the assessment of cardiac function and in prediction of intra- and post-operative hemodynamic instability and adverse cardiovascular events. Fragmentations on admission ECG may be useful for identifying patients with higher risk who will need additional support after CABG surgery.

Absence and Resolution of Fragmented QRS Predict Reversible Myocardial Ischemia With Higher Probability of ST Segment Resolution in Patients With ST Segment Elevation Myocardial Infarction

Background and ObjectivesFragmented QRS complexes (fQRS) are associated with increased morbidity and mortality. The causative relationship between fQRS and cardiac fibrosis has been shown, but whether the presence and the number of fQRS on admission of electrocardiogram (ECG) predicts ST segment resolution in patients undergoing primary percutaneous coronary intervention (p-PCI) has not been investigated until now.Subjects and MethodsThis study included one hundred and eighty-four consecutive patients with ST elevation myocardial infarction (STEMI) who underwent p-PCI. The presence or absence of fQRS on pre and post-PCI ECG and their relation with myocardial infarction and reperfusion parameters were investigated.ResultsPatients with fQRS on admission of ECG or newly developed fQRS after p-PCI had increased inflammatory markers, higher cardiac enzyme levels, increased pain to balloon time, prolonged QRS time, more extended coronary involvement and more frequent Q waves on ECG in comparison to patients with absence or resolved fQRS. The presence and higher number of fQRS on admission or post-PCI ECGs were significantly related with low percent of ST resolution and myocardial reperfusion parameters. The area under the receiver operating characteristics curve values for the presence and number of fQRS to detect Thrombolysis in Myocardial Infarction Blush Grade 0 and 1, were 0.682 and 0.703.ConclusionIn our study, fQRS was significantly related to infarction and myocardial reperfusion parameters before and after p-PCI. Successful myocardial reperfusion by p-PCI caused the reduction in number of fQRS and QRS time with higher ST resolution. fQRS may be useful in identifying the patients at higher cardiac risk with increased ischemic jeopardized or infarcted myocardium, and persistent or newly developed fQRS may predict low percent of ST segment resolution in patients undergoing p-PCI.

The importance of fragmented QRS complexes in prediction of myocardial infarction and reperfusion parameters in patients undergoing primary percutaneous coronary intervention

The QRS complex fragmentations (fQRS) frequently seen on admission electrocardiograms (ECGs) with narrow or wide QRS complex are associated with increased morbidity and mortality. The causative relationship between fQRS and cardiac fibrosis is known, but the relation of fragmented QRS before and after primary percutaneous coronary intervention (p-PCI) with myocardial infarction and reperfusion parameters has not been studied until now. The study included 184 consecutive patients with ST elevation myocardial infarction (STEMI) who underwent p-PCI. Presence or absence of fQRS on pre- and post-PCI ECGs and its change following PCI were investigated. In addition, independent predictors of fQRS were also investigated. Patients with significant organic valve disease and patients having any QRS morphology with QRS duration ?120 ms as well as patients with permanent pacemakers were excluded from the study. Patients with fQRS on admission ECG had higher leukocyte counts (p=0.001), higher CK-MB (p=0.001) and troponin levels (p=0.005), increased pain to balloon time (p=0.004), higher Killip score (p<0.001), prolonged QRS time (p<0.001), higher Gensini score (p<0.001) and more frequent Q waves on ECG (p<0.001) in comparison to patients with non-fragmented QRS. In addition, these patients usually had an infarction of anterior territory related to a lesion in proximal LAD and wider jeopardized myocardium (p<0.001). fQRS was significantly related to infarction and myocardial reperfusion parameters before and after p-PCI. In the setting of STEMI, absence of fQRS on admission ECG predicted increased ST resolution, higher reduction in QRS duration, and better myocardial reperfusion. FQRS may be useful in identifying patients at higher cardiac risk with larger areas of ischemic jeopardized or necrotic myocardium.